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M. A. Andreichikov

Publications and source records attributed to M. A. Andreichikov.

14 recordsLinked to original sources
arXiv2019

Dense Quark-Gluon Plasma in strong magnetic fields

A non-perturbative (np) method of Field Correlators (FCM) was applied to study QCD at temperatures above the deconfinement transition ($1<T/T_c<3,~T_c\sim0.16~GeV$) and nonzero baryon densities (baryon chemical potential $μ_B<0.5~GeV$) in an external uniform magnetic field ($eB<0.5~GeV^2$). Within FCM, the np high-temperature dynamics is embodied in the Polyakov loop and in the Debye mass due to the Color-Magnetic Confinement. Analytic expressions for quark pressure and magnetic susceptibility were obtained. The expressions were represented as series and in integral form. Magnetic susceptibility was found to increase rapidly with temperature and slowly with density. The results at the zero density limit are in agreement with lattice data.

hep-ph↗
arXiv2018

Chiral physics in the magnetic field with quark confinement contribution

The standard chiral perturbation theory is known to predict much weaker effects in magnetic field, than found in numerical lattice data. To overcome this disagreement we are using the effective chiral confinement Lagrangian, $L_{ECCL}$, containing both chiral and quark degrees of freedom, in the presence of external magnetic field. Without magnetic fields $L_{ECCL}$ reduces to the ordinary chiral Lagrangian $L_{EC L}$, yielding in the lowest order $O(\partial_μφ)^2$ all known relations, and providing explicit numerical coefficients in the higher $O(p^4, p^6)$ orders. The inclusion of the magnetic field in $L_{ECCL}$ strongly modifies ECL results for chiral condensates, coupling constants $f_π, f_K$ and masses of chiral mesons. The resulting behavior contains the only parameter -- the string tension $σ$, is roughly proportional to $O\left( \frac{eB}σ\right)$ and agrees very well with lattice data. These results show that the magnetic field acts not only on the chiral degrees of freedom $(φ_π)$, but also on quarks in the quark-chiral Lagrangian, which produce much stronger effect.

hep-ph↗
arXiv2017

Nonperturbative QCD thermodynamics in the external magnetic field

The thermodynamics of quarks and gluons strongly depends on the vacuum colormagnetic field, which grows with the temperature $T$, so that spatial string tension $σ_s ={\rm const}~ g^4 (T) T^2$. We investigate below what happens when one imposes in addition constant magnetic field and discover remarkable structure of the resulting thermodynamic potential.

hep-ph↗
arXiv2017

Nonperturbative quark-gluon thermodynamics at finite density

Thermodynamics of the quark-gluon plasma at finite density is studied in the framework of the Field Correlator Method, where thermodynamical effects of Polyakov loops and colormagnetic confinement are taken into account. Having found good agreement with numerical lattice data for zero density, we calculate pressure $P(T,\,μ)$ for $0 <μ< 400$ MeV and $150 <T< 1000$ MeV. For the first time the explicit intergral form is found in this region,demonstrating analytic structure in the complex $μ$ plane. The resulting multiple complex branch points are found at the Roberge-Weiss values of $\operatorname{Im}\,μ$, with $\operatorname{Re}\,μ$ defined by the values of Polyakov lines and colormagnetic confinement.

hep-ph↗
arXiv2017

The Evolution of Meson Masses in a Strong Magnetic Field

Spectra of $q \bar{q}$ hadrons are investigated in the framework of the Hamiltonian obtained from the relativistic path integral in external homogeneous magnetic field. The spectra of all 12 spin-isospin s-wave states, generated by $π$ and $ρ$ mesons with different spin projections, are studied both analytically and numerically on the lattice as functions of (magnetic field) $eB$. Results are in agreement and demonstrate three types of behavior, with characteristic splittings predicted by the theory.

hep-ph↗
arXiv2016

Mesons in ultra-intense magnetic field: an evaded collapse

Spectra of $q \bar q$ mesons are investigated in the framework of the Hamiltonian obtained from the relativistic path integral in external homogeneous magnetic field. The spectra of all 12 spin-isospin s-wave states generated by $π$- and $ρ$-mesons with different spin projections, are studied analytically as functions of the field strength. Three types of behavior with characteristic splittings are found. The results are in agreement with recent lattice calculations.

hep-ph↗
arXiv2013

Neutron in Strong Magnetic Fields

Relativistic world-line Hamiltonian for strongly interacting 3q systems in magnetic field is derived from the path integral for the corresponding Green's function. The neutral baryon Hamiltonian in magnetic field obeys the pseudomomentum conservation and allows a factorization of the c.m. and internal motion. The resulting expression for the baryon mass in magnetic field is written explicitly with the account of hyperfine, OPE and OGE (color Coulomb) interaction. The neutron mass is fast decreasing with magnetic field, losing 1/2 of its value at eB~0.25 GeV^2 and is nearly zero at eB~0.5 GeV^2. Possible physical consequences of the calculated mass trajectory of the neutron, M_n(B), are presented and discussed.

hep-ph↗
arXiv2013

Magnetic Field Focusing of Hyperfine Interaction in Hydrogen

We find a new correction to the hydrogen atom ground state hyperfine energy levels splitting in magnetic field. It can be interpreted as magnetic focusing of the wave function at the origin. The effect might be within the reach of experiment.

hep-ph↗
arXiv2013

Meson Spectrum in Strong Magnetic Fields

We study the relativistic quark-antiquark system embedded in magnetic field. The Hamiltonian containing confinement, one gluon exchange and spin-spin interaction is derived. We analytically follow the evolution of the lowest meson states as a functions of MF strength. Calculating the one gluon exchange interaction energy and spin-spin contribution we have observed, that these corrections remain finite at large magnetic fields, preventing the vanishing of the total rho-meson mass at some B_crit, as previously thought. We display the rho masses as functions of magnetic field in comparison with recent lattice data.

hep-ph↗
arXiv2012

Asymptotic freedom in strong magnetic field

Perturbative gluon exchange interaction between quark and antiquark, or in a 3q system, is enhanced in magnetic field and may cause vanishing of the total q\bar q or 3q mass, and even unlimited decrease of it - recently called the magnetic collapse of QCD. The analysis of the one-loop correction below shows a considerable softening of this phenomenon due to q\bar q loop contribution, similarly to the Coulomb case of QED, leading to approximately logarithmic dumping of gluon exchange interaction at large magnetic field.

hep-ph↗
arXiv2012

Magnetic Field Induced Effects in Quark Matter

Quark--gluon matter produced in relativistic heavy--ion collisions(RHIC and LHC) is subject to a super--strong magnetic field(MF) $\sim 10^{18} - 10^{20} G$. Quark matter(QM) response to MF allows to get a new insight on its properties. We give a cursory glance on MF induced effects.

hep-ph↗
arXiv2012

Quark-Antiquark System in Ultra-Intense Magnetic Field

We study the relativistic quark-antiquark system embedded in magnetic field (MF). The Hamiltonian containing confinement, color Coulomb and spin-spin interaction is derived. We analytically follow the evolution of the lowest neutral meson state as a function of MF strength. Calculating the color Coulomb energy $V_{Coul}$ we have observed the unbounded negative (at least in the limit of large $N_c$) contribution at large MF which makes the mass negative for $eB> eB^{QCD}_{crit}$. We display the $π^0$ and $ρ^0$ masses as functions of MF in comparison with recent lattice data.

hep-ph↗